The invention relates to a method for measuring an adhesive strength of a multilayer material having at least two layers such as a plain bearing, and more specifically to a method for measuring the adhesive strength of a copper or nickel or zinc plating layer on a steel back, or a copper or nickel or zinc strike plating layer on a bearing with an overlay, or an aluminum alloy or Kelmet alloy layer.
In the prior art, there have been proposed such measuring methods as the knife test, heat treatment blister test and folding test. However, such prior methods have involved the following disadvantages:
(1) It is impossible to measure adhesive strength quantitatively.
(2) Particular test pieces must be prepared separately from actual products for the measurement of adhesive strength.